The research proposed in this application is addressed mainly to the mammilian basal forebrain organization. The objectives are: (1) a continuing effort of improving the experimental techniques used in light and electron microscopic mapping of central nervous pathway, (2) the application of these techniques to the analysis of higher order olfactory pathways, including (3) the centrifugal pathways to the olfactory bulb, (4) the olfacto-amygdalo-diencephalic connections, and (5) the anatomical relations between the allocortex and the basal ganglia.